Question

The width of the depletion region in a P-N junction diode is.
A). Increased by the reverse bias
B). Increase by forwarding bias
C). Decrease by the reverse bias
D). Independent of the bias voltage

Answer 1

Hint: Study about the P-N junction diode. Understand the concept of conduction in the case of the P-N junction diode. Try to understand what happens to the P-N junction diode when we apply forward bias voltage and reverse bias voltage to the diode.

Complete step-by-step solution:
A P-N junction diode is formed by joining one P-type and one N-type diode. It allows current to flow in one direction only. In the other direction, it blocks the current.

If we apply a positive voltage to the diode i.e. positive terminal is connected towards the P-type and the negative terminal is towards the N-type, it can give the free electrons and holes extra energy to cross the junction, where the junction width or the width of the depletion layer is decreased. It is called forward bias.
when we apply a negative voltage to the diode i.e. a positive terminal is connected towards the N-type and the negative terminal is towards the P-type, the junction width, or the width of the depletion layer is increased. It is called reverse bias. This happens because when we apply reverse bias voltage the electrons are drifted away from the junction and hence, conduction is not possible.
So, the width of the depletion region in a P-N junction diode is increased by reverse bias.
The correct option is (A)

Note: When a P-N junction diode is in the forward biased condition the width of the depletion region decreases and current can pass through the diode. When the diode is in reverse bias the width of the depletion region is increased making it difficult for the charge carriers to cross the junction current cannot flow through the diode.